During development of software, debug operations for finding errors in the software are carried out. To perform a debug operation efficiently, it is effective to acquire information items concerning processing states, such as the current contents of a variable, as logs, at important processing points of the debug process. Further, for checking an operating state of software mounted on a device, if information items e.g. on the contents of variables in process, are acquired as logs, it is possible to facilitate analysis of the operating state of the software. Such information concerning states of software during execution of a program is called a trace log. In the trace log, details of processing, events, data communication history, etc. occurring on a computer are recorded together with the date and time of each occurrence thereof. By making use of the trace log, debug operations during development of software, and analysis operations for specifying causes of abnormality can be facilitated. In many cases, trace logs are coded to reduce the amount of data.
As a technique for acquiring a trace log, there has been proposed e.g. a technique of inserting a log output command for recording a process of execution into a source code, to thereby record the process of execution only on points related to attention-paid portions designated by a user. In this technique, an identifier number is caused to be included in log data, and the correspondence between the identifier number and other information, such as a file number or the like, is managed by data of another identifier (see e.g. Japanese Laid-Open Patent Publication No. 2000-207246).
However, conventionally, if there are trace logs in a mixed manner which are acquired during execution of a plurality of programs which are based on source codes different in version number, it is impossible to determine which version number of a source code contains commands causing generation of each trace log. As a consequence, it has been difficult to accurately analyze the operation of the software using the trace logs.